1. Field of the Invention
The present invention generally relates to apparatus for harvesting fruits or nuts from plants, and more particularly, the present invention relates to a harvesting apparatus that is adapted to transmit shaking forces to the trunk of the plant to be harvested.
2. Description of the Prior Art
One type of vibratory harvester particularly suited to harvest berries from vines or bushes grown in rows includes a shaker mechanism having fingers or arms adapted to penetrate the branches of the vines or bushes and to vibrate the branches to dislodge berries therefrom. Examples of this type of harvester are disclosed in the following U.S. Pat. Nos.: 3,184,908 issued to D. Rust on May 25, 1965; 3,396,521 issued to H. McKibben et al on Aug. 13, 1968; and 3,485,027 issued to R. Ganger on Dec. 23, 1969. The major problem with the vibratory finger type of harvester is that the fingers crush some of the berries during the harvesting process. Thus, some of the berries are damaged and some juice is expressed from the berries during harvesting thereby adversely affecting both the quality and quantity of the berry harvest. Also, the excessive amount of juice expressed during harvesting can unduly contaminate the shaker assembly and the berry collection system of the harvester.
U.S. Pat. No. 3,344,591 to Christie et al discloses a vibratory finger type of berry harvester that includes a shaker mechanism comprising a pair of vertical, transversely spaced shaker rotors that have fingers adapted to penetrate the branches of the vines or bushes. The rotors are positively driven to cause the rotors to oscillate and to rotate generally forwardly at a speed proportional to the speed of the vehicle. As disclosed in the patent, each rotor is driven by a sun gear oscillated about a given position through the action of a crank mechanism driven by an eccentric drive unit. Although this type of harvester is generally satisfactory in terms of dislodging a high percentage of the ripe berries from bushes or vines, it is subject to the same problems mentioned above in connection with other types of finger type shaker mechanisms; that is to say, too many of the berries are crushed by the fingers thereby ruining the quality and quantity of the berry output and unduly contaminating the shaker assembly and collection system of the harvester. Also, the sun gear and eccentric crank drive units are relatively expensive to manufacture and difficult to maintain.
U.S. Pat. No. 3,413,789 to Studer also discloses a vibratory finger type of fruit harvester adapted to harvest fruits and nuts from trees, bushes, and the like. The Studer patent discloses a vehicle-mounted shaker assembly that includes a rotor comprising a single row of radially extending arms, and the rotor is mounted for rotation about a vertical axis such that the arms extend laterally into the branches of the tree. The rotor is free to rotate so that the arms move in direct relationship to the forward speed of the vehicle as they are engaged by the trees or bushes, and eccentric weight vibration producing mechanisms are directly secured to the rotor. In one embodiment described in the Studer patent, two eccentric weights are mounted on the rotor and are positively driven in a relationship such that the weights always rotate 180.degree. out of phase with each other. The angular positional relationship of the weights and their equidistant spacing from the rotor axis is such that the forces induced by the weights combine additively to oscillate the rotor about its axis of rotation while inducing minimal vibration loading forces on the rotor support. The main objective of the invention of the Studer patent is stated therein to be the provision of a rotor type of shaker assembly that developes a circumferential vibration in the rotor which has no appreciable directional component (such as would tend to shake the harvester vehicle or rotor support so severely as to produce crystallization of the metal parts therein).
Another type of berry harvester includes parallel bars adapted to tightly grip the trunk of the plant while oscillating laterally to shake the fruit therefrom. Paddles are also used to rotate against the limbs and foliage to disrupt the vibrations induced by the gripping bars on the foliage to further aid in dislodging the fruit. Examples of this type of harvester are disclosed in U.S. Pat. No. 3,187,493 issued to E. Harrett on June 8, 1965 and U.S. Pat. No. 3,229,453 issued to E. Harrett on Jan. 18, 1966.
Another vibratory harvester particularly designed to continuously harvest grape vines includes an arrangement of parallel ski-shaped bars adapted to be oscillated laterally to strike the trunks of grape vines. An example of such type of harvester is the Pulsator model harvester manufactured by Up-Right Harvesters of Selma, Calif. Such grape harvester includes a shaker assembly that is pivotally mounted to an elevated portion of the frame of the harvester vehicle that overlies the vines. The shaker assembly includes the pair of ski-shaped striker bars that are adapted to slide and impact against opposite sides of the trunks of the vines during harvesting with only one of the striker bars engaging a trunk at a time. The striker bars are swingingly mounted at each side of the shaker assembly upon four-bar linkages, and the bars are driven by eccentric crank units to cause bars to laterally oscillate as the harvester is moved down a row of vines. The bars are oscillated in timed relation by right angle drive linkages connected between the eccentric crank units.